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    <title>Apache Tutorial: .htaccess files</title>
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    <h1 align="CENTER"><code>.htaccess</code> files</h1>
    <!-- INDEX BEGIN -->

    <ul>
      <li><a href="#what">What they are/How to use them</a></li>

      <li><a href="#when">When (not) to use <code
      class="file">.htaccess</code></a> files</li>

      <li><a href="#how">How directives are applied</a></li>

      <li><a href="#auth">Authentication example</a></li>

      <li><a href="#ssi">Server side includes example</a></li>

      <li><a href="#cgi">CGI example</a></li>

      <li><a href="#troubleshoot">Troubleshooting</a></li>
    </ul>
    <!-- Index End -->

    <table border="1">
      <tr>
        <td valign="top"><strong>Related Modules</strong><br />
         <br />
         <code><a href="../mod/core.html">core</a></code><br />
         <code><a href="../mod/mod_auth.html">mod_auth</a></code><br />
         <code><a href="../mod/mod_cgi.html">mod_cgi</a></code><br />
         <code><a href="../mod/mod_include.html">mod_include</a><br />
        </code> <a href="../mod/mod_mime.html">mod_mine</a><br />
         </td>

        <td valign="top"><strong>Related Directives</strong><br />
         <br />
         <code><a
        href="../mod/core.html#accessfilename">AccessFileName</a></code><br />
         <code><a
        href="../mod/core.html#allowoverride">AllowOverride</a></code><br />
         <code><a href="../mod/core.html#options">Options</a></code><br />
         <code><a
        href="../mod/mod_mime.html#addhandler">AddHandler</a></code><br />
         <code><a
        href="../mod/mod_mime.html#sethandler">SetHandler</a></code><br />
         <code><a
        href="../mod/core.html#authtype">AuthType</a></code><br />
         <code><a
        href="../mod/core.html#authname">AuthName</a></code><br />
         <code><a
        href="../mod/mod_auth.html#authuserfile">AuthUserFile</a></code><br />
         <code><a
        href="../mod/mod_auth.html#authuserfile">AuthGroupFile</a></code><br />
         <code><a href="../mod/core.html#require">Require</a></code><br />
         </td>
      </tr>
    </table>
    <hr />

    <h2><a id="what" name="what">What they are/How to use them</a></h2>

    <p><code>.htaccess</code> files (or "distributed configuration files")
    provide a way to make configuration changes on a per-directory basis. A
    file, containing one or more configuration directives, is placed in a
    particular document directory, and the directives apply to that
    directory, and all subdirectories thereof.</p>

    <p>Note: If you want to call your <code>.htaccess</code> file something
    else, you can change the name of the file using the <code><a
    href="../mod/core.html#accessfilename">AccessFileName</a></code>
    directive. For example, if you would rather call the file
    <code>.config</code> then you can put the following in your server
    configuration file:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>AccessFileName .config</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>What you can put in these files is determined by the <code><a
    href="../mod/core.html#allowoverride">AllowOverride</a></code>
    directive. This directive specifies, in categories, what directives
    will be honored if they are found in a <code>.htaccess</code> file. If
    a directive is permitted in a <code>.htaccess</code> file, the
    documentation for that directive will contain an Override section,
    specifying what value must be in <code>AllowOverride</code> in order
    for that directive to be permitted.</p>

    <p>For example, if you look at the documentation for the <a
    href="../mod/core.html#adddefaultcharset">AddDefaultCharset</a>
    directive, you will find that it is permitted in <code>.htaccess</code>
    files. (See the Context line in the directive summary.) The <a
    href="../mod/directive-dict.html#Context">Override</a> line reads
    "<code>FileInfo</code>". Thus, you must have at least
    "<code>AllowOverride FileInfo</code>" in order for this directive to be
    honored in <code>.htaccess</code> files.</p>

    <p>Example:</p>

    <blockquote>
      <table>
        <tr>
          <td><a
          href="../mod/directive-dict.html#Context">Context:</a></td>

          <td>server config, virtual host, directory, .htaccess</td>
        </tr>

        <tr>
          <td><a
          href="../mod/directive-dict.html#Override">Override:</a></td>

          <td>FileInfo</td>
        </tr>
      </table>
    </blockquote>

    <p>If you are unsure whether a particular directive is permitted in a
    <code>.htaccess</code> file, look at the documentation for that
    directive, and check the Context line for ".htaccess."</p>

    <h2><a id="when" name="when">When (not) to use .htaccess files</a></h2>

    <p>In general, you should never use <code>.htaccess</code> files unless
    you don't have access to the main server configuration file. There is,
    for example, a prevailing misconception that user authentication should
    always be done in <code>.htaccess</code> files. This is simply not the
    case. You can put user authentication configurations in the main server
    configuration, and this is, in fact, the preferred way to do
    things.</p>

    <p><code>.htaccess</code> files should be used in a case where the
    content providers need to make configuration changes to the server on a
    per-directory basis, but do not have root access on the server system.
    In the event that the server administrator is not willing to make
    frequent configuration changes, it might be desirable to permit
    individual users to make these changes in <code>.htaccess</code> files
    for themselves. This is particularly true, for example, in cases where
    ISPs are hosting multiple user sites on a single machine, and want
    their users to be able to alter their configuration.</p>

    <p>However, in general, use of <code>.htaccess</code> files should be
    avoided when possible. Any configuration that you would consider
    putting in a <code>.htaccess</code> file, can just as effectively be
    made in a <a href="../mod/core.html#directory">&lt;Directory&gt;</a>
    section in your main server configuration file.</p>

    <p>There are two main reasons to avoid the use of
    <code>.htaccess</code> files.</p>

    <p>The first of these is performance. When <code>AllowOverride</code>
    is set to allow the use of <code>.htaccess</code> files, Apache will
    look in every directory for <code>.htaccess</code> files. Thus,
    permitting <code>.htaccess</code> files causes a performance hit,
    whether or not you actually even use them! Also, the
    <code>.htaccess</code> file is loaded every time a document is
    requested.</p>

    <p>Further note that Apache must look for <code>.htaccess</code> files
    in all higher-level directories, in order to have a full complement of
    directives that it must apply. (See section on <a href="#how">how
    directives are applied</a>.) Thus, if a file is requested out of a
    directory <code>/www/htdocs/example</code>, Apache must look for the
    following files:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>/.htaccess<br />
           /www/.htaccess<br />
           /www/htdocs/.htaccess<br />
           /www/htdocs/example/.htaccess</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>And so, for each file access out of that directory, there are 4
    additional file-system accesses, even if none of those files are
    present. (Note that this would only be the case if .htaccess files were
    enabled for /, which is not usually the case.)</p>

    <p>The second consideration is one of security. You are permitting
    users to modify server configuration, which may result in changes over
    which you have no control. Carefully consider whether you want to give
    your users this privilege.</p>

    <p>Note that it is completely equivalent to put a .htaccess file in a
    directory <code>/www/htdocs/example</code> containing a directive, and
    to put that same directive in a Directory section <code>&lt;Directory
    /www/htdocs/example&gt;</code> in your main server configuration:</p>

    <p><code>.htaccess</code> file in <code>/www/htdocs/example</code>:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>AddType text/example .exm</code>
          </td>
        </tr>
      </table>
    </blockquote>

    <p><code>httpd.conf</code></p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>&lt;Directory
          /www/htdocs/example&gt;<br />
           AddType text/example .exm<br />
           &lt;/Directory&gt;</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>However, putting this configuration in your server configuration
    file will result in less of a performance hit, as the configuration is
    loaded once when Apache starts, rather than every time a file is
    requested.</p>

    <p>The use of <code>.htaccess</code> files can be disabled completely
    by setting the <code>AllowOverride</code> directive to "none"</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>AllowOverride None</code> </td>
        </tr>
      </table>
    </blockquote>

    <h2><a id="how" name="how">How directives are applied</a></h2>

    <p>The configuration directives found in a <code>.htaccess</code> file
    are applied to the directory in which the <code>.htaccess</code> file
    is found, and to all subdirectories thereof. However, it is important
    to also remember that there may have been <code>.htaccess</code> files
    in directories higher up. Directives are applied in the order that they
    are found. Therefore, a <code>.htaccess</code> file in a particular
    directory may override directives found in <code>.htaccess</code> files
    found higher up in the directory tree. And those, in turn, may have
    overridden directives found yet higher up, or in the main server
    configuration file itself.</p>

    <p>Example:</p>

    <p>In the directory <code>/www/htdocs/example1</code> we have a
    <code>.htaccess</code> file containing the following:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>Options +ExecCGI</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>(Note: you must have "<code>AllowOverride Options</code>" in effect
    to permit the use of the "<code><a
    href="../mod/core.html#options">Options</a></code>" directive in
    <code>.htaccess</code> files.)</p>

    <p>In the directory <code>/www/htdocs/example1/example2</code> we have
    a <code>.htaccess</code> file containing:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>Options Includes</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>Because of this second <code>.htaccess</code> file, in the directory
    <code>/www/htdocs/example1/example2</code>, CGI execution is not
    permitted, as only <code>Options Includes</code> is in effect, which
    completely overrides any earlier setting that may have been in
    place.</p>

    <h2><a id="auth" name="auth">Authentication example</a></h2>

    <p>If you jumped directly to this part of the document to find out how
    to do authentication, it is important to note one thing. There is a
    common misconception that you are required to use
    <code>.htaccess</code> files in order to implement password
    authentication. This is not the case. Putting authentication directives
    in a <code>&lt;Directory&gt;</code> section, in your main server
    configuration file, is the preferred way to implement this, and
    <code>.htaccess</code> files should be used only if you don't have
    access to the main server configuration file. See above for a
    discussion of when you should and should not use <code>.htaccess</code>
    files.</p>

    <p>Having said that, if you still think you need to use a
    <code>.htaccess</code> file, you may find that a configuration such as
    what follows may work for you.</p>

    <p>You must have "<code>AllowOverride AuthConfig</code>" in effect for
    these directives to be honored.</p>

    <p><code>.htaccess</code> file contents:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>AuthType Basic<br />
           AuthName "Password Required"<br />
           AuthUserFile /www/passwords/password.file<br />
           AuthGroupFile /www/passwords/group.file<br />
           Require Group admins</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>Note that <code>AllowOverride AuthConfig</code> must be in effect
    for these directives to have any effect.</p>

    <p>Please see the <a href="auth.html">authentication tutorial</a> for a
    more complete discussion of authentication and authorization.</p>

    <h2><a id="ssi" name="ssi">Server side includes example</a></h2>

    <p>Another common use of <code>.htaccess</code> files is to enable
    Server Side Includes for a particular directory. This may be done with
    the following configuration directives, placed in a
    <code>.htaccess</code> file in the desired directory:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>Options +Includes<br />
           AddType text/html shtml<br />
           AddHandler server-parsed shtml</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>Note that <code>AllowOverride Options</code> and <code>AllowOverride
    FileInfo</code> must both be in effect for these directives to have any
    effect.</p>

    <p>Please see the <a href="ssi.html">SSI tutorial</a> for a more
    complete discussion of server-side includes.</p>

    <h2><a id="cgi" name="cgi">CGI example</a></h2>

    <p>Finally, you may wish to use a <code>.htaccess</code> file to permit
    the execution of CGI programs in a particular directory. This may be
    implemented with the following configuration:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>Options +ExecCGI<br />
           AddHandler cgi-script cgi pl</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>Alternately, if you wish to have all files in the given directory be
    considered to be CGI programs, this may be done with the following
    configuration:</p>

    <blockquote>
      <table cellpadding="10">
        <tr>
          <td bgcolor="#eeeeee"><code>Options +ExecCGI<br />
           SetHandler cgi-script</code> </td>
        </tr>
      </table>
    </blockquote>

    <p>Note that <code>AllowOverride Options</code> must be in effect for
    these directives to have any effect.</p>

    <p>Please see the <a href="cgi.html">CGI tutorial</a> for a more
    complete discussion of CGI programming and configuration.</p>

    <h2><a id="troubleshoot" name="troubleshoot">Troubleshooting</a></h2>

    <p>When you put configuration directives in a <code>.htaccess</code>
    file, and you don't get the desired effect, there are a number of
    things that may be going wrong.</p>

    <p>Most commonly, the problem is that <code><a
    href="../mod/core.html#allowoverride">AllowOverride</a></code> is not
    set such that your configuration directives are being honored. Make
    sure that you don't have a <code>AllowOverride None</code> in effect
    for the file scope in question. A good test for this is to put garbage
    in your <code>.htaccess</code> file and reload. If a server error is
    not generated, then you almost certainly have <code>AllowOverride
    None</code> in effect.</p>

    <p>If, on the other hand, you are getting server errors when trying to
    access documents, check your Apache error log. It will likely tell you
    that the directive used in your .htaccess file is not permitted.
    Alternately, it may tell you that you had a syntax error, which you
    will then need to fix.</p>
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